There have been proposed a variety of display apparatuses in which display circuits and light receiving circuits are arranged on the same substrate and which are capable of displaying an image and also of receiving light from an outside (see, for example, Japanese Patent Laid-Open No. 2004-318067 and Japanese Patent Laid-Open No. 2004-318819). Each of the light receiving circuits detects light that is emitted from an object (e.g., a pen) that has an external light source such as a light emitting diode (LED), light that is originally emitted from a backlight and then reflected and returned from a finger or pen that is in contact with a screen, or the like, and supplies a light receiving signal as a result of the detection of the light to a signal processing circuit or the like in a subsequent stage.
The signal processing circuit or the like in the subsequent stage, for example, analyzes a location on the screen which a user has specified with the finger or the pen, thereby analyzing information entered by the user. Thus, the more light receiving circuits are arranged on the substrate, the higher detection precision is achieved. However, the more light receiving circuits are arranged on the substrate, the greater a load for processing the light receiving signal becomes. Therefore, when there is not a need for a high light receiving resolution, the light receiving resolution is sometimes set at a lower value than that of a display resolution by thinning the light receiving circuits arranged on the substrate.
However, thinning the light receiving circuits arranged on the substrate might produce a problem. Even if the light receiving circuits are thinned, acquisition of location information will not suffer a significant problem when detecting a relatively large object such as the finger. However, when the detection target object is a small object such as a stylus or a pen with a fine tip, a loss of light receiving information because of the thinning of the light receiving circuits will be so great that the location information of the detection target object cannot be detected accurately.